Electronic controller apparatus and control method

Abstract

An electronic controller apparatus comprises a controller circuit for controlling an external load and a power supply circuit to power the controller circuit. A switch is adapted to alternately be conductive to bypass the power supply circuit from the input or allow the power supply circuit to obtain power from the input. A linear operation of the switch is used to reduce current and voltage waveform distortion when power is being obtained from the input.

The invention claimed is: 
     
       1. An electronic controller apparatus, adapted to connect in series with an AC supply and an external load, the apparatus comprising:
 a controller circuit for controlling the external load; 
 a power supply circuit to power the controller circuit, comprising an AC input for receiving energy, wherein said AC input is adapted to connect in series with the AC supply and the external load; and 
 a switch connected across the input and in parallel with the power supply circuit, adapted alternately to be conductive to bypass the power supply circuit from the AC input or to allow the power supply circuit to obtain power from the AC input, 
 wherein for a first type of AC supply of a sufficient operating current, the switch is adapted to continue a current of said first type of AC supply by alternately:
 being fully conductive; and 
 operating in a linear state to allow the power supply circuit to obtain power from the AC input, 
 
 thereby to allow the sufficient current to flow continuously from said first type of AC supply and through the external load. 
 
     
     
       2. An apparatus as claimed in  claim 1 , comprising a rectifier for rectifying the AC input before delivery to the power supply circuit, and the power supply circuit comprises at least one of:
 a storage capacitor; 
 a linear power supply; and 
 a switched mode power supply. 
 
     
     
       3. An apparatus as claimed in  claim 1 , wherein the power supply circuit is connected in series with the external load via the AC input, and said controller circuit is for controlling the external load. 
     
     
       4. An apparatus as claimed in  claim 3 , wherein the energy is received from an AC current of the external load, and wherein the AC current comprises, for different modes of the external load, a standby current of the external load and an operating current of the external load which is larger than the standby current, and wherein said operating current comprises said first type of AC supply. 
     
     
       5. An apparatus as claimed in  claim 4 , wherein for the first type of AC supply, the switch is adapted to alternate between:
 the fully conductive state when an output voltage of the power supply circuit reaches an upper threshold, such that the power supply circuit is bypassed from the AC input; and 
 the linear state in which the power supply circuit is adapted to obtain a portion of the operating current from the AC input while the switch allows a rest of the operating current to flow through when the output voltage of the power supply reaches a lower threshold. 
 
     
     
       6. An apparatus as claimed in  claim 5 , wherein for the first type of AC supply, the duration of the conductive state is larger than the duration of linear state. 
     
     
       7. An apparatus as claimed in  claim 4 , wherein when the AC current is the standby current, as a second type of AC supply, the switch is adapted to alternate between:
 a fully conductive state when an output voltage of the power supply circuit reaches an upper threshold, such that the power supply circuit is bypassed from the AC input; and 
 the linear state and a fully non-conductive state when the output voltage of the power supply reaches a lower threshold, to allow the power supply circuit to obtain power from the AC input, 
 wherein the duration of the fully conductive state is smaller than the duration of the linear state and the fully non-conductive state. 
 
     
     
       8. An apparatus as claimed in  claim 7 , comprising a feedback circuit for controlling the switch to alternate between the different states. 
     
     
       9. An apparatus as claimed in  claim 8 , wherein the feedback circuit comprises:
 a voltage sensing circuit to sense a voltage output of the power supply circuit; 
 a comparing circuit to compare the sensed voltage with a reference voltage and output a voltage level to operate the switch in the different states; and 
 a buffering component in a feedback path of the comparing circuit, wherein said buffering component is adapted to generate a slew rate to the voltage level to the switch. 
 
     
     
       10. An apparatus as claimed in  claim 9 , wherein:
 for the first type of AC supply, the buffering component is adapted to generate the slew rate such that the voltage level is kept in a control voltage range of the linear state before the power supply circuit is sufficiently charged by a portion of the operating current; 
 for the second type of AC supply, the buffering component is adapted to generate the slew such as to allow the voltage level to enter a control voltage range of the fully non-conducive state before the power supply circuit is sufficiently charged by the standby current; and 
 the buffering component comprises a capacitor with capacitance in the range 22 nF to 220 nF connected between the output of the comparing circuit and the reference voltage. 
 
     
     
       11. An apparatus as claimed in  claim 1 , wherein the external load comprises a lamp having the standby mode without light emission and the operating mode with light emission. 
     
     
       12. An apparatus as claimed in  claim 1 , wherein the controller comprises an RF transmission circuit for providing RF control signals to the external load. 
     
     
       13. A lighting system comprising:
 an AC lamp, having a standby mode without light emission and an operating mode with light emission; and 
 an apparatus as claimed in  claim 1  in series with the lamp and adapted to control a mode of the lamp, wherein the lamp comprises the external load, and thereby receives as the AC input an AC lamp current. 
 
     
     
       14. A method of powering a controller circuit which is for controlling an external load, wherein the controller circuit is adapted to connect in series with an AC supply and the external load, the method comprising:
 receiving energy at an AC input of a power supply circuit, wherein said AC input is adapted to connect in series with the AC supply and the external load; and 
 in a cycle, alternately setting a switch connected across the AC input to be conductive to bypass the power supply circuit from the AC input and setting the switch to allow the power supply circuit to obtain power from the AC input, 
 wherein when allowing the power supply circuit to obtain power from the input, for a first type of AC supply of a sufficient operating current, the method comprises operating the switch to continue a current of said first type of AC supply by alternately:
 being conductive; and 
 operating in a linear state to allow the power supply circuit to obtain power from the AC input, 
 
 thereby to allow the sufficient current to flow continuously from said first type of AC supply and through the external load. 
 
     
     
       15. A method as claimed in  claim 14 , comprising receiving energy as an AC current of the external load, and wherein the AC current comprises for different modes of the external load a standby current of the external load and an operating current of the external load which is larger than the standby current,
 wherein the method comprises alternating the setting of the switch between a conductive state, such that the power supply circuit is bypassed from the AC input, and a control state in which the power supply circuit obtains power from the AC input, 
 wherein when the AC current is a standby current, the duration of the conductive state is smaller than the duration of the control state, and the control state is a fully non-conductive state, and 
 when the AC current is a load operating current, the duration of the conductive state is larger than the duration of the control state, and the control state comprises said operation of the switch in the linear state.